[es6] Implement spec compliant ToPrimitive in the runtime.

This is the first step towards a spec compliant ToPrimitive
implementation (and therefore spec compliant ToNumber, ToString,
ToName, and friends).  It adds support for the @@toPrimitive
symbol that was introduced with ES2015, and also adds the new
Symbol.prototype[@@toPrimitive] and Date.prototype[@@toPrimitive]
initial properties.

There are now runtime functions for %ToPrimitive, %ToNumber and
%ToString, which do the right thing and should be used as fallbacks
instead of the hairy runtime.js implementations.  I will do the
same for the other conversion operations mentioned by the spec in
follow up CLs.  Once everything is in place we can look into
optimizing things further, so that we don't always call into the
runtime.

Also fixed Date.prototype.toJSON to be spec compliant.

R=mstarzinger@chromium.org, yangguo@chromium.org
BUG=v8:4307
LOG=y

Review URL: https://codereview.chromium.org/1306303003

Cr-Commit-Position: refs/heads/master@{#30434}
42 files changed
tree: 5a80032e9f681eeb9710e74380a57fc2dcf52cfb
  1. benchmarks/
  2. build/
  3. include/
  4. infra/
  5. samples/
  6. src/
  7. test/
  8. testing/
  9. third_party/
  10. tools/
  11. .clang-format
  12. .gitignore
  13. .ycm_extra_conf.py
  14. AUTHORS
  15. BUILD.gn
  16. ChangeLog
  17. codereview.settings
  18. DEPS
  19. LICENSE
  20. LICENSE.strongtalk
  21. LICENSE.v8
  22. LICENSE.valgrind
  23. Makefile
  24. Makefile.android
  25. Makefile.nacl
  26. OWNERS
  27. PRESUBMIT.py
  28. README.md
  29. WATCHLISTS
README.md

V8 JavaScript Engine

V8 is Google's open source JavaScript engine.

V8 implements ECMAScript as specified in ECMA-262.

V8 is written in C++ and is used in Google Chrome, the open source browser from Google.

V8 can run standalone, or can be embedded into any C++ application.

V8 Project page: https://code.google.com/p/v8/

Getting the Code

Checkout depot tools, and run

    fetch v8

This will checkout V8 into the directory v8 and fetch all of its dependencies. To stay up to date, run

    git pull origin
    gclient sync

For fetching all branches, add the following into your remote configuration in .git/config:

    fetch = +refs/branch-heads/*:refs/remotes/branch-heads/*
    fetch = +refs/tags/*:refs/tags/*